Erasing shield



ERASING' SHIELD Filed Sept. 20, 1941 INVENTOR. mm w. mp5; I

BY W

Patented Oct. 13, 1942 UNITED STATES PATENT OFFICE ERASING SHIELD FredW. Radio], South Orange, N. J.

Application September 20, 1941, Serial No. 411,619 3 Claims. (01.120-41) The usual erasing shields for typewriters support the paperconcentrically to the platen roller of the typewriter.

This is very unsatisfactory because thereby the contact pressure betweenthe eraser and the thus formed sharply convex surface of the paper isextremely localized thereby causing an uneven erasing effect.Furthermore the convex form of the paper surface results not only in aperspective shortening, impairing somewhat the legibility in the processof correction, but also in a tendency of the paper and carbon paper tobecome dislodged and crumpled or even torn by such process, andfrequently also in the necessity of moving the platen to effect completeerasure. The invention eliminates these disadvantages and speeds up theerasing operation by combining with the known concave platen engagingsurface a less curved and preferably plane or substantially flat papersupporting surface.

In the drawing, the object of the invention is shown by way of example.

Fig. 1 is a plan view of the new shield;

Fig. 2 is a section on the line 2-2 of Fig. 1.

The new shield consists of the shield body proper a and the handle I)directed at an angle thereto. Both may form together a unitary integralpiece of suitable materialv such as plastic, metal, glass, fibre, etc.

The lower surface of the shield a has the known form of a concavesurface curved so as to fit around part of the surface of a platenroller.

In accordance with the invention the opposite or upper surface of thebody a is not concentric to the surface 0, but is a substantially fiat,i. e. plane surface d. This plane surface supports the sheet to becorrected so that the erasing isdone on a substantially flat and rigidsurface which is much more practical and mechanically suitable than acurved surface.

For making possible the relative eccentricity of the surfaces 0 and dthe upper and lower ends of the body a are thickened at ,f and 9compared with the middle section h, the thickened part having a somewhatrhomboidal crosssection.

The parts I) and 1 meet in the edge i, and the parts (2' and a meet inthe edge m. Both these edges may be conveniently rounded or blunted sothat a blunt corner is formed in cross-section as shown in Fig. 2. Thesection g is relatively thin and preferably tapering or wedge shaped forclose insertion between the papers and for convenience when placing theshield in position.

The modification shown and described above is preferred. However, forsome special purposes the surface d maybe not simply plane, but may be aflatly curved surface of a concavity opposite that of the surface 0 forexerting some guiding effect upon the eraser during erasing.

The modification shown and described is supposed to be made from rigidmaterial.

If desired, however, the object of the invention may be made of aflexible material like vulcanized rubber. In that event thecross-section, in a condition out of use, need not correspond to theform shown in Fig. 2, but in that out of use condition, the surface 0for instance may be straight and the surface d may be concave, providedthe form is selected so that in use, when the surface 0 is conformed tothe platen by the pressure, as explained, the surface d has the formshown in Fig. 2 or an analogous form, as described.

Attention is called to the fact that, as may be seen from Fig. 2, obtuseangles are formed, in cross-section, at the edges 2' and m. In erasingthe paper is bent around these edges by the pressure of the fingerswhereby the danger of dislodging or crumpling of the paper iseliminated. On the other hand by the obtuseness of said angles,'and/orthe bluntness of said edges respectively, the formation of objectionablepermanent folding lines in the paper is avoided.

Of course, the provision of an angle or edge such as described at onlyone end of the surface d would sufiice; preferably, however, both endsare shaped in this manner.

What I claim is:

1. An erasing shield comprising a dihedral body having a rear part witha concave seating surface adapted to encompass part of the platen rollerof a typewriter and a front part with a paper supporting surface of aconsiderably fiatter curvature than said platen roller.

2. An erasing shield comprising adihedral body having a rear part with aconcave seating surface adapted to encompass part of the platen rollerof a typewriter and a front part with a substantially plane papersupporting surface.

3. An erasing shield, comprising, in combination, a body having a rearpart with a concave seating surface adapted to encompass part of theplaten roller of a typewriter and a front part with a paper supportingsurface of a considerably flatter curvature than said platen roller, anda wedge shaped part at one end of said body.

FRED W. RADE'L.

